1. Field
The teachings in accordance with the exemplary embodiments of this present invention generally relate to a diagnostic cartridge and a control method for diagnostic cartridge, and more particularly to a diagnostic cartridge mounted with a membrane having a valve function, and capable of providing a washing function through generation of air segment, and a control method for diagnostic cartridge.
2. Background
In the past, a patient had to visit a hospital whenever there is a need that requires a medical doctor's check-up or diagnosis. Nowadays, however, the patient can easily get a medical check-up at any place using a simple diagnostic cartridge. Researches for the diagnostic cartridge have been briskly waged to a direction to reduce a user inconvenience and to enhance accuracy.
A variety of structures for diagnostic cartridges has been developed for measuring samples and for mixing specimens. Generally, the structure is such that the samples and specimens are moved and mixed through a plurality of channels, and reaction therefrom is advised to a user. In this case, a method for effectively controlling the movement of samples and specimens is very important for adequate mixing the measurement samples and specimens.
Particularly, there is a difficulty in controlling movement of liquid due to unexpected force such as cohesiveness, because each size of channels is very small, and the samples and specimens are usually liquid. If the samples and specimens are reversely flown, checking cannot be properly performed, and chances are that a disposal diagnostic cartridge is discarded even without a checking.
In order to solve the aforementioned problems, attempts have been made to adjust pressure inside channels, but a comprehensive solution is yet to be found through adjustment of pressure inside the channels due to a complicated connection of channels inside the cartridge. Furthermore, only air pressure is not sufficient enough to move liquid inside the complicatedly-connected channels to a desired position, and in this case, a separate device must be equipped to obtain additional energy for moving liquids such as samples and specimens to the desired position due to restriction of size of the diagnostic cartridge.
Meanwhile, nonspecific absorption of protein among proteins or to a wall surface of a structure is a frequent phenomenon that occurs in a biosensor field. Generally, possibility of generating a nonspecific absorption on a wall surface of structure is relatively high due to high area ratio relative to area versus volume, as scale becomes smaller like micro size or nano size.
In order to reduce the nonspecific absorption phenomenon, a wall surface of channel is directly blocked using polymer, or a large amount of coating agents (or a large quantity of proteins present in samples) is made to flow inside the channels along with the samples to indirectly reduce the nonspecific absorption phenomenon.
A washing function in a micro-fluidic device (chip or cartridge) measuring sandwich immunoassay by way of an electrochemical method is very important for a high-sensitive quantitative analysis. Particularly, the nonspecific absorption that occurs on an electrode of enzyme conjugated antibody or a wall surface of channels about an electrode functions to increase a background signal and to act as a factor that interrupts the high-sensitive quantitative analysis.
A conventional immune response protocol has used a method of reducing the nonspecific absorption by using a separate washing solution. However, the conventional method has a disadvantage in that a large quantity of washing buffer is needed, and particularly long-term storage and transfer must be additionally realized in addition to substrate solution in case of immune diagnosis equipment for point-of-care diagnosis.